This invention relates to a novel antiulcer drug comprising Ikarugamycin as its active ingredient. Ikarugamycin is a compound whose pharmacological action has not yet been known at all except that it has been known merely as an antibiotic having a trichomonacidal effect and showing a weak antibacterial effect against gram positive bacteria.
The present inventors have made an intensive study on the pharmacological activity of Ikarugamycin and accomplished the present invention based on the finding that the compound exhibits an excellent antiulcer activity.